Previously I had a Nokia 7.1 (Android 9) when I started to notice this issue. Every few time, the older images I had on my Download folder disappeared without I doing nothing. From time to time it happened again. I let this pass. Every time that ocurred, I manually download the images again, because I needed to have those images there.
Today, I have another smartphone (Multilaser MS50X, a brazilian cellphone with Android 8.1) and exactly after a month of started using it, the older images of my Download folder disappeared again!!!
I've checked some apps that I think it could be doing something like that:
* Google Chrome (downloads data to this folder)
* Google Photos (sync and backup images)
* File Manager + (access to data and folders)
* Quickpic (gallery app)
But no one have an option to "automatically delete Download folders content after a while".
I don't have any Clean App, neither use the function "Free up space" of Android. Also none of those cellphones had an option like "storage booster" or "smart storage" like state on this thread: Android phone automatically deletes photos?
Any clue where can I look? It's annoying
Update: When I open Google Photos, go to 'Photos on device', and select 'Download', I can see all the deleted images (the images that should be on that folder and it doesn't)